Semiconductor component and method for producing a semiconductor component

ABSTRACT

A semiconductor component includes a semiconductor body with a semiconductor layer sequence having an active region, provided for generating coherent radiation, and an indicator layer. With respect to an interface which delimits the semiconductor body in regions in a vertical direction, on that side of said interface which is remote from the active region, the semiconductor body has a web-like region extending in a vertical direction between the interface and a surface of the semiconductor body. The indicator layer has a material composition that differs from that of the material of the web-like region which adjoins the indicator layer. A distance between the indicator layer and the surface is at most of the same magnitude as a distance between the interface and the surface.

This patent application is a national phase filing under section 371 ofPCT/DE2009/000334, filed Mar. 9, 2009, which claims the priority ofGerman patent application 10 2008 016 489.5, filed Mar. 31, 2008 and 102008 021 674.7, filed Apr. 30, 2008, each of which is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

The present application relates to a semiconductor component and to amethod for producing a semiconductor component.

BACKGROUND

Edge emitting semiconductor laser diodes with ridge waveguide geometry(ridge waveguide laser diodes) typically have a web-type regionprovided, in particular, for wave guiding in a lateral direction. Inorder to produce the web-type region, semiconductor material may beremoved in regions by means of an etching method, wherein the etchingdepth may be set by way of the duration of the etching process. In thiscase, inhomogeneities of the material composition and of the thicknessof the semiconductor material which occur in a lateral direction, forinstance on account of fluctuations in the production process, make itmore difficult to effect uniform and reproducible formation of aweb-type region with a predetermined height. This may lead tofluctuations in operating characteristic variables for the semiconductorlasers, for instance in the laser threshold, the gradient of thepower-current characteristic curve and the mode behavior.

SUMMARY

One aspect of the invention specifies a semiconductor component that hasimproved optoelectronic properties and may be produced in a simplifiedmanner. Furthermore, a method is specified with which a semiconductorcomponent may be reliably produced in a simple manner.

A semiconductor component comprises, in accordance with one exemplaryembodiment, a semiconductor body with a semiconductor layer sequencehaving an active region, provided for generating coherent radiation, andan indicator layer. The semiconductor body has an interface whichdelimits the semiconductor body in regions in a vertical direction. Onthat side of the interface which is remote from the active region, thesemiconductor body has a web-like region extending in a verticaldirection between the interface and a surface of the semiconductor body.The indicator layer has a material composition that differs from that ofthe material of the web-like region which adjoins the indicator layer. Adistance between the indicator layer and the surface is at most of thesame magnitude as a distance between the interface and the surface.

The distance between the indicator layer and the active region may beset as early as during the preferably epitaxial deposition of thesemiconductor layer sequence of the semiconductor body. The web-likeregion may be formed in a particularly reproducible manner, inparticular with regard to its extent in a vertical direction and/or itsdistance from the active region, wherein the vertical extent of theweb-like region is at least of the same magnitude as the distancebetween the indicator layer and the surface.

In one configuration variant, the interface is formed by means of theindicator layer. In this case, the distance between the indicator layerand the surface may correspond or at least be close to the distancebetween the interface and the indicator layer. By way of example, thedistance between a top side of the indicator layer which is remote fromthe active region and the interface may be at most 100 nm, preferably atmost 50 nm.

In particular, the top side of the indicator layer may form theinterface. The top side may furthermore be embodied as a planar orsubstantially planar area which separates the web-like region from theindicator layer. Consequently, the distance between the interface andthe active region is substantially predetermined by the distance betweenthe top side of the indicator layer and the active region as early asduring the deposition of the semiconductor body.

In a further configuration variant, a distance between the indicatorlayer and the interface is at most 70 nm. In other words, a distancebetween an underside of the indicator layer which faces the activeregion and the active region is at most 70 nm greater than a distancebetween the interface and the active region. In this case, the indicatorlayer may be arranged completely within the web-like region.

A web-like region is understood to mean, in particular, a region whichhas, in a lateral direction, a smaller extent than the active region.The active region therefore projects beyond the web-like region at leastin regions in a lateral direction.

A lateral direction is considered to be a direction which runs in a mainextension plane of the semiconductor layers of the semiconductor bodyand perpendicularly to a main propagation direction of the radiationwhich, during operation, is generated in the active region and is to beamplified, in particular.

A vertical direction is correspondingly understood to mean a directionwhich runs perpendicularly to the main extension plane of thesemiconductor layers of the semiconductor body.

In one preferred configuration, the semiconductor body has a chargecarrier barrier, which is formed on that side of the active region whichfaces the web-like region. A radiative recombination of charge carriersthat are injected into the semiconductor body during the operation ofthe semiconductor component may thus be restricted to the active regionin an improved manner. The threshold for the operating current at whichthe generation of coherent radiation commences may be lowered.

In one configuration variant, the charge carrier barrier is formed bymeans of the indicator layer. Therefore, in addition to the simplifiedformation of the web-like region, the indicator layer may serve toensure that the recombination of charge carriers is effected efficientlywithin the active region.

In an alternative configuration variant, the indicator layer is spacedapart from the charge carrier barrier. In particular, the indicatorlayer may be at a greater distance from the active region than thecharge carrier barrier. The indicator layer may therefore be formed onthat side of the charge carrier barrier which is remote from the activeregion. Indicator layer and charge carrier barrier may thus be chosenindependently of one another, for instance with regard to their materialcomposition. Furthermore, the distance between the web-like region andthe active region may thus be set largely independently of the positionof the charge carrier barrier.

The charge carrier barrier preferably has a greater transmissivity forone charge type than for the other charge type. By way of example, thecharge carrier barrier may be embodied as an electron barrier whichallows holes to pass through unimpeded or at least largely unimpeded. Anelectron barrier is preferably arranged in a p-conducting region of thesemiconductor layer sequence or adjoins a p-conducting region. Inparticular, an electron barrier itself may be doped in p-conductingfashion.

Correspondingly, a hole barrier is preferably arranged in ann-conducting region or adjoins an n-conducting region and is furthermorepreferably doped in n-conducting fashion.

In one preferred configuration, a waveguide layer is formed on that sideof the active region which faces the web-like region. The waveguidelayer is provided, in particular, for guiding the radiation that is tobe generated and/or amplified in the active region in a verticaldirection.

The indicator layer may be arranged between the waveguide layer and theactive region. In other words, the waveguide layer may be arranged onthat side of the indicator layer which is remote from the active region.A distance between the waveguide layer and the active region maytherefore be set in a simple manner by means of the indicator layer.Furthermore, in this case, the web-like region may extend into thewaveguide layer.

The indicator layer may also be arranged on that side of the waveguidelayer which is remote from the active region. In this case, thewaveguide layer may be formed outside the web-like region.

Furthermore, the indicator layer may also be formed in the waveguidelayer. In this case, therefore, material of the waveguide layer may bearranged on both sides of the indicator layer.

An indicator layer is understood to mean, in particular, a layer whichbrings about a significant change in at least one property of a processgas during a dry-chemical removal method with respect to a layerdisposed upstream in the removal direction. By monitoring this propertyit may be determined during production, in a precise and reproduciblemanner, when the indicator layer is reached.

In one preferred configuration, the indicator layer contains a materialhaving a higher resistance to a dry-chemical removal method than thematerial, in particular directly adjoining, on that side of theindicator layer which is remote from the active region. The formation ofa web-like region which extends in a vertical direction up to apredetermined distance from the active region may thus be realized in asimplified manner.

The semiconductor body preferably contains a III-V compoundsemiconductor material. With III-V semiconductor materials, highinternal quantum efficiencies may be achieved during the generation ofradiation.

In particular, the semiconductor body may contain a nitridic compoundsemiconductor material.

A nitridic compound semiconductor material is understood to mean amaterial which comprises a nitride III/N compound semiconductormaterial, preferably Al_(x)In_(y)Ga_(1-x-y)N, where 0≦x≦1, 0≦y≦1 andx+y≦1 hold true, in particular where x≠1, y≠1, x≠0 and/or y≠0. In thiscase, this material need not necessarily have a mathematically exactcomposition according to the above formula. Rather, it may have one ormore dopants and additional constituents which substantially do notchange the characteristic physical properties of theAl_(x)In_(y)Ga_(1-x-y)N material. For the sake of simplicity, however,the above formula only comprises the essential constituents of thecrystal lattice (Al, Ga, In, N), even if these may be replaced in partby small amounts of further substances.

Nitridic compound semiconductor materials are particularly suitable forgenerating radiation in the ultraviolet through the blue to the greenspectral range.

In one preferred configuration, the indicator layer has a compositionwhich, with regard to a group III material, for instance aluminum,indium or gallium, differs by at least 10 percentage points,particularly preferably by at least 20 percentage points, from thecomposition of a semiconductor layer of the web-like region whichadjoins the indicator layer. The greater the difference in the materialcomposition, the greater the extent to which the removal rates for thesesemiconductor layers may deviate from one another during production.

In one preferred development, the indicator layer has a higher aluminumcontent than the semiconductor layer of the web-like region whichadjoins the indicator layer. The aluminum content of the indicator layeris furthermore preferably at least 20%, particularly preferably at least30%.

In a further preferred configuration, the indicator layer contains anitridic compound semiconductor material and is particularly preferablylattice-matched relative to gallium nitride. The relative deviation ofthe lattice constant of the indicator layer from the lattice constant ofgallium nitride is preferably at most 5%, particularly preferably atmost 3%. In particular the stress of a semiconductor body with an activeregion based on a nitridic compound semiconductor material may thus bereduced.

In a further preferred configuration, a cladding layer is arranged atleast on one side of the active region. The cladding layer preferablyhas a lower refractive index than the waveguide layer. Wave guiding ofthe radiation generated in the active region during the operation of thesemiconductor component in the waveguide layer is thus simplified.

The cladding layer or at least one partial layer of the cladding layerfurthermore preferably contains Al_(x)In_(y)Ga_(1-x-y)N having an indiumcontent different from zero.

The gallium content is furthermore preferably at most 10%, such that1−x−y≦0.1 holds true. The cladding layer or at least the partial layerof the cladding layer may furthermore be lattice-matched relative togallium nitride.

In a further preferred configuration, a distance between the indicatorlayer and the active region is at most 400 nm, particularly preferablyat most 300 nm. The distance may be reduced to a greater extent and beat most 150 nm, preferably at most 120 nm, most preferably at most 70nm. The web-like region may thus be formed particularly close to theactive region. In particular, an indicator layer arranged so close tothe active region may be embodied as a charge carrier barrier.

In a further preferred configuration, a side area of the web-like regionruns at an angle of at most 30° with respect to a perpendicular to themain extension plane of the semiconductor layers of the semiconductorbody. In particular, the side area may run perpendicularly orsubstantially perpendicularly, for instance with a deviation from theperpendicular by at most 10°, to the main extension plane of the activeregion. Furthermore, the side area may run parallel to a mainpropagation direction of the radiation generated in the active region.In particular, the side area may run perpendicularly or substantiallyperpendicularly to a coupling-out area for the radiation.

In one preferred development, the semiconductor component is embodied asan edge emitting semiconductor laser component, in particular as asemiconductor laser component with ridge waveguide geometry.

In a method for producing a semiconductor component, in accordance withone embodiment, a semiconductor layer sequence having an active region,provided for generating radiation, and an indicator layer is provided.Material of the semiconductor layer sequence arranged on that side ofthe indicator layer that is remote from the active region is removed inregions by means of dry-chemical removal of the semiconductor layersequence, wherein a property of a process gas is monitored during theremoval and the reaching of the indicator layer is determined by meansof the change in the property of the process gas.

In this context, the term process gas encompasses in a broad meaningnon-ionized, partly ionized and ionized gas (plasma), which mayfurthermore contain removed semiconductor material.

Reactive ion etching (RIE) or chemical assisted ion beam etching (CAIBE)is suitable, by way of example, as a dry-chemical removal method.

In particular, during this method, semiconductor material removal whichis more extensive in a vertical direction may be ended or at leastgreatly reduced as soon as the indicator layer is reached. The thicknessof the semiconductor material remaining on the active region maytherefore be set by way of the thickness and the distance of theindicator layer from the active region as early as during the depositionof the semiconductor layer sequence.

In other words, during the method described, a predetermined removaldepth or a predetermined distance from the active region may be setlargely independently of the actual removal rate.

In one preferred configuration, a change in the material composition ofthe removed semiconductor material is determined by means of themonitored property of the process gas.

The monitored property may be, in particular, the spectral emissioncharacteristic of the process gas. Depending on the composition of theprocess gas, in this case the removed material may bring about, in atleast one spectral range, an emission that is characteristic of thematerial. Preferably, the intensity of this emission is higher, thelarger the amount of the material in the process gas.

In a further preferred configuration, the dry-chemical removal methodand the indicator layer are coordinated with one another in such a waythat material on the indicator layer is removed more slowly thanmaterial which is disposed directly upstream of the indicator layer asviewed in the removal direction. More widely, the dry-chemical removalmethod may be selective with respect to the material such that theremoval method stops at the level of the indicator layer or is at leastslowed down in such a way that no significant removal of the indicatorlayer takes place. The indicator layer may therefore fulfill thefunction of a stop layer for the removal method. The uncovering of theindicator layer in the predetermined regions may therefore be largelyindependent of the thickness of the material arranged on the indicatorlayer. Even in the case of an inhomogeneous layer thickness and/or aninhomogeneous material composition of the material arranged on theindicator layer in the main extension plane of the semiconductor layers,the indicator layer may thus be completely uncovered in thepredetermined regions. A thickness of the semiconductor material thatremains on the active region may therefore be made constant or at leastlargely constant in these regions.

In one preferred configuration, the indicator layer containsAl_(x)In_(y)Ga_(1-x-y)N and furthermore preferably has a higher aluminumcontent than the material disposed directly upstream of the indicatorlayer as viewed in the removal direction.

The process gas furthermore preferably contains oxygen at least attimes. As a result of oxygen being added to the process gas, the removalmethod may have a high selectivity with respect to the aluminum contentof the semiconductor layers. In particular, the removal rate may belower, the higher the aluminum content.

The semiconductor material may also be removed beyond the indicatorlayer. In particular, the method may be carried out in such a way thatthe removal method is initially stopped or at least slowed down uponreaching the indicator layer. Afterward, the method may be continued inmodified fashion such that the indicator layer is removed in theuncovered regions. More extensively, material disposed downstream of theindicator layer as viewed in the removal direction may also be removed.

As a result of stopping or slowing down the removal at the indicatorlayer, material of the semiconductor layer sequence may initially beremoved to a distance from the active region which is predetermined byway of the distance between the top side of the indicator layer and theactive region as early as during the deposition of the semiconductorlayer sequence. This removal to a predetermined distance from the activeregion may be effected independently of the actual removal rate and witha high homogeneity along the main extension plane of the semiconductorlayers.

Afterward, the indicator layer and furthermore underlying semiconductormaterial may be removed in regions, such that material of the indicatorlayer only remains in the web-like region.

In particular, the dry-chemical removal method may be modified after theindicator layer has been reached, in such a way that material of theindicator layer is removed with an increased removal rate.

In one preferred configuration, the method is carried out for aplurality of semiconductor layer sequences, wherein the semiconductorlayer sequences are respectively provided on separate carriers. Themethod may thus be carried out simultaneously for a plurality ofsemiconductor layer sequences, whereby the throughput during theproduction of the semiconductor components may be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

The method described is particularly suitable for producing asemiconductor component described further above. Therefore, featuresdescribed in connection with the method may also be employed for thesemiconductor component, and vice versa.

Further features, advantageous configurations and expediences willbecome apparent from the following description of the exemplaryembodiments in conjunction with the figures.

In the figures:

FIG. 1 shows a first exemplary embodiment of a semiconductor componentin schematic sectional view;

FIG. 2 shows a second exemplary embodiment of a semiconductor componentin schematic sectional view;

FIG. 3 shows a third exemplary embodiment of a semiconductor componentin schematic sectional view;

FIGS. 4A and 4B show a first exemplary embodiment of a method forproducing a semiconductor component on the basis of intermediate stepsrespectively illustrated in schematic sectional view; and

FIGS. 5A to 5C show a second exemplary embodiment of a method forproducing a semiconductor component on the basis of intermediate stepsrespectively illustrated in schematic sectional view.

Elements which are identical, of identical type or act identically areprovided with identical reference symbols in the figures.

The figures are in each case schematic illustrations and therefore notnecessarily true to scale. Rather, comparatively small elements and, inparticular, layer thicknesses may be illustrated with an exaggeratedsize for clarification purposes.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

A first exemplary embodiment of a semiconductor component 1 is shown inschematic sectional view in FIG. 1. The semiconductor component 1 isembodied as an edge emitting semiconductor laser with ridge waveguidegeometry and has a semiconductor body 2 with a semiconductor layersequence. The semiconductor layer sequence, which forms thesemiconductor body, is preferably deposited epitaxially, for instance bymeans of MOVPE or MBE. The semiconductor body 2 is arranged on a carrier20. The carrier 20 may be, for example, a growth substrate for thesemiconductor layer sequence. As an alternative, the carrier 20 may alsobe different from the growth substrate for the semiconductor layersequence.

The semiconductor layer sequence has an active region 21, provided forgenerating coherent laser radiation. Furthermore, the semiconductorlayer sequence comprises an indicator layer 3. The semiconductor body 2has an interface 30 which delimits the semiconductor body 2 in regionsin a vertical direction. A web-like region 4 is formed on that side ofthe indicator layer 3 which is remote from the active region 21. Theweb-like region 4 extends in a vertical direction between a surface 40of the semiconductor body 2 and the interface 30. The indicator layer 3has a top side 31 remote from the active region 21 and an underside 32facing the active region. The interface 30 is formed by means of theindicator layer 3.

In particular, the interface 30 may be at a distance of at most 100 nm,preferably at most 50 nm, from the top side 31 of the indicator layer 3.More extensively, the interface 30 may be formed by means of the topside 31 of the indicator layer 3, such that the distance between theindicator layer 3 and the surface 40 corresponds to the distance betweenthe interface 30 and the surface 40.

The web-like region 4 therefore extends in a vertical direction as faras the indicator layer 3. A side area 45 of the web-like region 4extends perpendicularly to a main extension plane of the semiconductorlayers of the semiconductor body 2.

In a lateral direction, the web-like region 4 covers the interface 30only in regions. Furthermore, in a lateral direction, the web-likeregion 4 has a smaller extent than the active region 21. The propagationof the mode of the radiation amplified in the active region 21 duringoperation in a lateral direction may thus be delimited.

Furthermore, the semiconductor layer sequence has a waveguide layer 22and a further waveguide layer 23, in which the radiation that isgenerated and furthermore to be amplified in the active region 21 duringoperation propagates. A cladding layer 24 and a further cladding layer25 are arranged on that side of the waveguide layer 22 which is remotefrom the active region 21 and, respectively, that side of the furtherwaveguide layer 23 which is remote from the active region 21. Thecladding layers 24, 25 expediently have a refractive index that is lessthan the refractive index of the respectively adjoining waveguide layers22, 23.

The semiconductor body 2 has a connection layer 26 on that side of thecladding layer 24 which is remote from the active region 21. Theconnection layer 26 expediently has the same conduction type as thecladding layer arranged between the connection layer and the activeregion 21.

Furthermore, the semiconductor component 1 has a first contact 51 and asecond contact 52, which are provided for externally making electricalcontact with the semiconductor body 2. The contacts 51, 52 areelectrically conductively connected to the semiconductor body 2 in sucha way that, during the operation of the semiconductor component 1, viathe contacts, charge carriers may be injected from two different sidesinto the active region 21 and may recombine there with emission ofradiation.

In the exemplary embodiment shown, the charge carriers are injected fromthe first contact 51 via the connection layer 26 into the active region21. In this case, the connection layer 26 forms the surface 40 of theweb-like region 4. In a departure from this, the connection layer 26 mayalso be dispensed with. In this case, the first contact 51 may directlyadjoin the cladding layer.

The contact layers 51, 52 preferably contain a metal, for instance gold,titanium, platinum, aluminum, silver, palladium, rhodium or nickel, or ametallic alloy comprising at least one of the metals mentioned.

The material composition of the semiconductor body 2 is described belowby way of example for a semiconductor component provided for generatingradiation in the ultraviolet and blue spectral range. The semiconductorlayers of the semiconductor body 2 in each case contain the nitridiccompound semiconductor material Al_(x)In_(y)Ga_(1-x-y)N. It goes withoutsaying that the construction described is also suitable for a differentsemiconductor material, in particular a different III-V compoundsemiconductor material. For generating radiation having a higherwavelength, Al_(x)In_(y)Ga_(1-x-y)P is suitable, in particular, foryellow to red radiation and Al_(x)In_(y)Ga_(1-x-y)As is suitable for redto infrared radiation. In the case of the material compositionsmentioned, 0≦x≦1, 0≦y≦1 and x+y≦1 respectively hold true, in particularwhere x≠1, y≠1, x≠0 and/or y≠0.

The indicator layer 3 contains a larger aluminum content than thewaveguide layer 22 of the web-like region 4, the waveguide layeradjoining the indicator layer 3.

The aluminum content of the indicator layer 3 is preferably at least30%, particularly preferably at least 50%. The material is furthermorepreferably chosen in such a way that the indicator layer islattice-matched with respect to GaN. By way of example, a layer havingan aluminum content of 82% and an indium content of 18% has the samelattice constant as GaN.

By comparison with an Al_(x)Ga_(1-x)N semiconductor layer, the decreasein the lattice constant as the aluminum content increases may becompletely or at least substantially compensated for in the case of anAl_(x)In_(y)Ga_(1-x-y)N layer as a result of the addition of indium. Thealuminum content may thus be increased without the stress increasing inthis case relative to gallium nitride.

Furthermore, the band gap of Al_(x)In_(y)Ga_(1-x-y)N increases as thealuminum content increases. Consequently, compared with the activeregion 21, the indicator layer 3 may have a high band gap and fulfillthe function of a charge carrier barrier 28.

The semiconductor layers arranged on different sides of the activeregion 21 preferably have mutually opposite conduction types. By way ofexample, the semiconductor layers of the web-like region 4 and of theindicator layer 3 may be doped in p-conducting fashion and thesemiconductor layers arranged between the active region 21 and thecarrier 20 may be doped in n-conducting fashion. In this case, theindicator layer 3 may be embodied as an electron barrier. For asufficiently high transmissivity for holes, the indicator layer in thiscase is preferably doped in heavily p-conducting fashion, for example,with magnesium.

The indicator layer 3 serving as a charge carrier barrier may directlyadjoin the active region 21.

In a departure from this, the indicator layer 3 may also be embodied ina manner spaced apart from the active region 21. The distance ispreferably at most 400 nm, particularly preferably at most 300 nm. Thedistance may be reduced to a greater extent and be at most 150 nm,preferably at most 120 nm, most preferably at most 70 nm. The closer tothe active region 21 the charge carrier barrier 28 is arranged, thegreater the extent to which the recombination of charge carriers may berestricted to the active region 21. That proportion of the chargecarriers injected into the semiconductor body 2 which recombines in theactive region 21 with emission of radiation may thus be increased. As aresult, the laser threshold may be lowered and the slope of thecharacteristic curve of the power of the generated radiation as afunction of the injected current (P-I characteristic curve) may beincreased.

In a departure from the first exemplary embodiment described withreference to FIG. 1, the top side 31 of the indicator layer 3 may alsobe spaced apart from the interface 30, wherein the distance between thetop side of the indicator layer 3 and the surface 40 is smaller than thedistance between the interface 30 and the surface 40. In this case,therefore, the indicator layer 3 projects into the web-like region 4.

More extensively, the indicator layer 3 may also be arranged completelywithin the web-like region 4. In this case, therefore, the interface 30is formed outside the indicator layer 3. The distance between theunderside 32 of the web-like region 4 and the interface 30 is preferablyat most 70 nm, particularly preferably at most 50 nm. The production ofsuch a semiconductor component will be described in connection withFIGS. 5A to 5C.

A second exemplary embodiment of a semiconductor component isillustrated schematically in sectional view in FIG. 2. This secondexemplary embodiment substantially corresponds to the first exemplaryembodiment described in connection with FIG. 1. In contrast thereto, thecladding layer 24, in particular the web-like region 4, has a partiallayer 240, which contains Al_(x)In_(y)Ga_(1-x-y)N having an indiumcontent different from zero.

With this partial layer 240, the cladding layer 24 may have lower stresswith respect to gallium nitride by comparison with an Al_(x)Ga_(1-x)Ncladding layer having the same aluminum content. The stress of thesemiconductor body 2 may thus be reduced.

The aluminum content of the partial layer 240 of the cladding layer 24may be lower than the aluminum content of the indicator layer 3. Theproduction of a web-like region 4 extending as far as the indicatorlayer 3 is thus simplified.

In a departure therefrom, the aluminum content of the partial layer 240of the cladding layer 24 may also be higher than the aluminum content ofthe indicator layer 3. In this case, the material of the web-like region4 which is arranged directly on that side of the indicator layer 3 whichis remote from the active region 21 preferably has a lower aluminumcontent than the indicator layer 3. The thickness of this materialhaving a lower aluminum content is preferably a thickness of between 20nm and 400 nm inclusive, particularly preferably between 50 nm and 300nm inclusive, for example, 150 nm.

In a departure from the exemplary embodiment described, the partiallayer 240 may also be arranged on that side of the active region 21which is remote from the web-like region 4. Furthermore, such a partiallayer may also be formed in each case on both sides of the activeregion. A plurality of such partial layers may also be provided. Thestress of the semiconductor body may thus be reduced to a greaterextent.

A third exemplary embodiment of a semiconductor component is illustratedin schematic sectional view in FIG. 3. This exemplary embodimentsubstantially corresponds to the first exemplary embodiment described inconnection with FIG. 1. In contrast thereto, the indicator layer 3 isembodied separately from the charge carrier barrier 28, wherein theindicator layer 3 and the charge carrier barrier 28 are arranged on thesame side of the active region 21. The waveguide layer 22 is arrangedbetween the charge carrier barrier 28 and the indicator layer 3. Theindicator layer 3 is therefore arranged on that side of the waveguidelayer 22 which is remote from the active region 21.

In this exemplary embodiment, the indicator layer 3, in particular withregard to the material, may be embodied largely independently of thecharge carrier barrier 28. Furthermore, the distance between theweb-like region 4 and the active region 21 may be set independently ofthe position of the charge carrier barrier 28.

A first exemplary embodiment of a method for producing a semiconductorcomponent is shown in FIGS. 4A and 4B on the basis of intermediate stepsillustrated schematically in sectional view. In this case, the method isdescribed by way of example on the basis of the production of asemiconductor component embodied in the manner described in connectionwith FIG. 1.

A semiconductor layer sequence 2 is provided on a carrier 20 (FIG. 4A).Only a part of the semiconductor layer sequence from which asemiconductor body for a semiconductor component emerges is shown, forthe sake of simplified illustration. However, a plurality ofsemiconductor bodies may be formed simultaneously alongside one another.

The semiconductor layer sequence 2 comprises an active region 21,provided for generating radiation, and an indicator layer 3. From a sideof the semiconductor layer sequence 2 which is remote from the carrier20, material of the semiconductor layer sequence is removed in regionsby means of a dry-chemical method (FIG. 4B).

By way of example, reactive ion etching, for instance ICP-RIE(inductively coupled plasma RIE) or parallel plate RIE, or chemicalassisted ion beam etching is suitable for this purpose. A property of aprocess gas, for instance of a plasma with portions of the material justremoved, is monitored during the dry-chemical removal. In particular,the material composition of the semiconductor material just removed maybe determined during removal as a result of the monitoring of theprocess gas.

When the indicator layer 3 is reached, the monitored property of theprocess gas changes, such that the reaching of a predetermined removaldepth is indicated. The accuracy with which the actual removal depthreaches the predetermined removal depth is therefore largely independentof the actual removal rate.

By way of example, the spectral composition of the radiation emitted bythe process gas may be monitored. On the basis of the intensity of theradiation emitted in a spectral range that is characteristic of thematerial to be removed, the material composition of the material justremoved may thus be deduced. By way of example, an increase in thealuminum content in the removed material may be detected as a result ofan increase in the radiation power in a spectral range that ischaracteristic of aluminum.

With regard to the material composition, the indicator layer 3 differsfrom the semiconductor material disposed upstream as viewed in theremoval direction such that the reaching of the indicator layer ismanifested in a significant change in the spectral intensitydistribution of the process gas.

By way of example, the indicator layer 3 may have an aluminum contentthat is higher than the aluminum content of the material disposeddirectly upstream of the indicator layer in the removal direction. Inparticular, an AlInGaN indicator layer having an aluminum content of atleast 30% is suitable. The indicator layer 3 may be embodied, inparticular, in a manner free of gallium. By way of example, theindicator layer may have an aluminum content of 82% and an indiumcontent of 18%. Such a semiconductor layer is lattice-matched to a GaNlayer.

A selectivity of the removal rate with respect to the aluminum contentmay be increased, for example, by oxygen being added into the processgas. The higher the aluminum content, the lower the etching rate in thiscase. What may thus be achieved is that the removal process is almostcompletely stopped upon reaching the indicator layer 3. Materialdisposed upstream of the indicator layer may be completely removedlargely independently of layer thickness fluctuations in thepredetermined regions. Inhomogeneities of the layer thickness and/or ofthe material composition of the material to be removed along the mainextension plane of the semiconductor layers may thus be compensated forin a simple manner. The yield that may be obtained during the productionof the semiconductor components may thus be increased.

For externally making electrical contact with the semiconductorcomponent, contact areas may be deposited (not explicitly illustrated inFIG. 4B), for instance by means of vapor deposition or sputtering, onthe semiconductor body 2 as described in connection with FIG. 1.

By means of the method described, it is generally possible to form acutout in a semiconductor layer sequence, the depth of which may bepredetermined by way of the position of the indicator layer 3 as earlyas during the production of the semiconductor layer sequence. Incontrast to an etching method in which the etching depth is set by wayof the product of expected etching rate and etching duration, in thecase of the method described the predetermined removal depth may beachieved even in the case of deviations of the etching rate.

The method has been described merely by way of example on the basis ofthe production of an edge emitting semiconductor laser component withridge waveguide geometry, and is generally suitable for the productionof semiconductor components in which the removal depth greatlyinfluences the properties of the semiconductor component.

The method described is distinguished, in particular, by the fact thatthe thickness of the semiconductor material remaining below the removedmaterial after conclusion of the removal is not dependent, or is onlyslightly dependent, on fluctuations of the layer thickness and/or of thematerial composition of the material to be removed. In particular, themethod may be carried out simultaneously for a plurality ofsemiconductor layer sequences without production-dictated fluctuationsbetween the different semiconductor layer sequences significantlyjeopardizing the yield of functional semiconductor components.Therefore, in one method step, a plurality of semiconductor layersequences, which, by way of example, are in each case deposited on awafer, may be simultaneously be subjected to the removal process.

A second exemplary embodiment of a method for producing a semiconductorcomponent is shown in FIGS. 5A to 5C on the basis of intermediate stepsillustrated schematically in sectional view. This second exemplaryembodiment substantially corresponds to the first exemplary embodimentdescribed in connection with FIGS. 4A and 4B. In contrast thereto, thesemiconductor layer sequence of the semiconductor body 2 is embodied inthe manner described in connection with FIG. 3. The indicator layer 3 istherefore spaced apart from the active region 21 (FIG. 5A).

As illustrated in FIG. 5B, the indicator layer 3 is uncovered inregions. This may be done in the manner described in connection withFIG. 4B. The material arranged on the indicator layer 3 may thus beremoved independently of the actual removal rate to a predetermineddistance from the active region 21.

Afterward, the removal method may be continued in a modified manner suchthat material of the indicator layer 3 is removed with an increasedremoval rate (FIG. 5C). The increased removal rate may be obtained, forexample, by a reduction or a complete setting of the addition of oxygento the process gas. In this way, the web-like region 4 may be producedsuch that the indicator layer 3 runs in the web-like region.Furthermore, material of the underlying waveguide layer 22 may also beremoved. The interface 30 is formed by means of the waveguide layer 22.In a departure from the exemplary embodiment shown, the interface 30 mayalso be formed by means of a different layer arranged between the activeregion 21 and the indicator layer 3, for example, by means of the chargecarrier barrier 28.

The invention is not restricted by the descriptions on the basis of theexemplary embodiments. Rather, the invention encompasses any novelfeature and also any combination of features, which in particularincludes any combination of features in the patent claims, even if thisfeature or this combination is not explicitly specified in the patentclaims or the exemplary embodiments.

The invention claimed is:
 1. A semiconductor component, comprising asemiconductor body with a semiconductor layer sequence having an activeregion, provided for generating coherent radiation, and an indicatorlayer, wherein the semiconductor body has an interface that delimits thesemiconductor body in regions in a vertical direction; the semiconductorbody has a web-like region on that side of the interface which is remotefrom the active region, the web-like region extending in a verticaldirection between the interface and a surface of the semiconductor body;the indicator layer has a material composition that differs from that ofa material of the web-like region that adjoins the indicator layer; adistance between the indicator layer and the surface is at most of asame magnitude as a distance between the interface and the surface;wherein the indicator layer contains Al_(x)In_(y)Ga_(1-x-y)N where0.3≦x≦1, 0≦y≦1 and x+y≦1 and is lattice-matched relative to GaN.
 2. Thesemiconductor component as claimed in claim 1, wherein a distancebetween the indicator layer and the interface is at most 70 nm.
 3. Thesemiconductor component as claimed in claim 1, wherein the interface isformed by means of the indicator layer.
 4. The semiconductor componentas claimed in claim 1, wherein a charge carrier barrier is formed onthat side of the active region that faces the web-like region andwherein the charge carrier barrier is formed by means of the indicatorlayer.
 5. The semiconductor component as claimed in claim 1, wherein acharge carrier barrier is formed on that side of the active region whichfaces the web-like region, wherein the indicator layer is spaced apartfrom the charge carrier barrier.
 6. The semiconductor component asclaimed in claim 1, wherein a waveguide layer is formed on that side ofthe active region which faces the web-like region.
 7. The semiconductorcomponent as claimed in claim 6, wherein the indicator layer is arrangedbetween the waveguide layer and the active region and wherein theindicator layer has a higher Al content than the material of theweb-like region which adjoins the indicator layer.
 8. The semiconductorcomponent as claimed in claim 6, wherein the indicator layer is arrangedon that side of the waveguide layer which is remote from the activeregion.
 9. The semiconductor component as claimed in claim 1, furthercomprising a cladding layer with a partial layer arranged at least onone side of the active region and wherein the partial layer containsindium.
 10. The semiconductor component as claimed in claim 6, whereinthe indicator layer is formed in the waveguide layer.
 11. Thesemiconductor component as claimed in claim 1, wherein the aluminumcontent of the indicator layer is at least 50%.